The "Science" of Love

“IT’S THE BRAIN, CUPID!”

February is the month of romance in pagan and Christian religions. February 14 was considered  to be the beginning of bird mating season in Great Britain. The Catholic Church designated February 14 as the feast day of St. Valentine but no longer celebrates it as a holiday. There are at least three different stories of why Valentine was designated a saint. About 1 billion St.Valentine Day cards are purchased each year; 85% by women. (Christmas cards top the charts at 2.6 billion).  Valentine cards inundate us with the symbol of love, the heart.

The earliest artistic depictions of the heart were in the shape of an inverted pine cone, apex pointing up. For a variety of speculative reasons this image was inverted to the one familiar to us today.    If you believe that this image mimics the rounded buttocks of a forward-bending woman, then you will also agree that Cupid’s phallic arrow is correctly aimed.

Theories also abound as to why the heart was considered the source of love. Perhaps the easiest one to accept is that the heart quickens when we are “in love”. It certainly does so when we are making love. It may be the only aerobic exercise that many get.

Today, science tells us that the heart is not the source of love. It is the brain, the source of the chemicals and hormones surging and ebbing which apparently govern our emotions. There are three phase of love. Testosterone and estrogen fuel the first phase, lust. Their levels are controlled by the hypothalamus area of the brain, influenced in large part by our individual genetic make-up.

Dopamine, and its close associate serotonin, fuels the second phase of love, attraction. Dopamine increases our “wanting”, our “desires”, and reaches its highest blood levels during orgasm or after cocaine ingestion.

The third phase of love, attachment, depends on oxytocin, the so-called “cuddle hormone”. Oxytocin promotes  commitment and long-term relationships. It enhances mother-child bonding during breast feeding. It’s effects do diminish over time.  Marital counselors often counsel troubled couples whose surges of dopamine and oxytocin may have become less frequent to try more sex . Maybe this diagram of oxytocin should replace the heart as the symbol of true love.

     Somehow I can’t see Hallmark going for this in a big way.

Vasopressin, which is released after sex , also promotes attachment. Science knows this from the “voles experiment”.  Male vole are apparently known for multiple sex acts with the same partner out of proportion to the need to advance the species. They have less sex with, and decrease their  protection of, their partner when given an antagonist to vasopressin. 

There is no single “libido hormone”.  Testosterone and estrogen, the “lust” chemicals, are the most closely associated with libido. Viagra is merely a selectively acting vasodilator. (It was originally developed to help patients with restrictive lung disease or angina; arguably the most famous “unintended discovery” since penicillin; at least to certain stockholders.)  It does not arouse anybody. What does?

According to most psychologists, our brains do. We unconsciously build a list of attractive attributes of a potential mate, called, of course, a “love map”. When we encounter someone who has one or two of those attractive traits, we seek more encounters. If what we learn about the person matches more and more of our love map, the chemicals take over and guide our subsequent actions. (Could explain the “3-dates-before-sex rule” accepted by many today as a culture norm.)

Despite the millions spent on perfumes and colognes, there is little to indicate that smell is an important element in our love map. Smell, the detection of pheromones, is very important in the reproductive cycle of the rest of the animal kingdom, but not apparently for us. Legend has it that when Napoleon Bonaparte wrote Josephine to arrange a love tryst, he said, “I’m coming home — please don’t wash.” Recent research on the scientific basis of love suggests that the famous general may have been onto something that guaranteed his success in the bedroom as well as on the battlefield.

The intriguing “smelly T-shirt” experiment , first done in 1995 and repeated with the same result in 2005, is one of the few suggestions that smell might have a role in love.  Young woman were asked to smell T-shirts worn for two nights by young men and indicate which ones they found “pleasing”. Most of the women favored the T-shirts worn by men who had DIFFERENT immune genetic profiles than they did. This was interpreted as of positive evolutionary value because the presence of different immunological genes in the offspring would broaden their protection from disease organisms.  Many other efforts to come up with a “sniff test” for the perfect mate have not been successful.  (Eat your heart out Axe Peace super bowl 2014 commercial .) 

Despite all this scientific hodgepodge, deep down we all probably don’t want to believe that the mystery of human love can be explained by genetic maps and certain chemical blood levels. To quote one of the world’s most famous scientific skeptics, Alfred Einstein, when asked if he ever thought of trying to have “the perfect child”  with Marilyn Monroe, he said: “I would be afraid that the child might have my looks and her brains.”

Einstein might have had the last word on the relationship between science and love when he said, “Gravity is not responsible for people falling in love.”